The present invention relates to the production of aerated material, especially chewing gum. By "aerated" is meant that the density of the material is reduced by the designed introduction of air, or one or a mixture of specific gases. The material can be any which is continuous and extrudible, such as gums and taffy.
Since such materials tend to be relatively viscous, the aeration of the material is not straightforward. It is all too easy to form voids in the product which render the product unsightly or otherwise of unacceptable aesthetic and/or performance characteristics. In addition, if the aeration forms voids which appear at the surface and break open, the desired reduction in density is prevented from occurring.
Attempts have been made in the past to aerate gums, as typified by U.S. Pat. No. 4,491,596 and U.S. Pat. No. 5,045,326. Such attempts have lacked the reliability, versatility and simplicity of the techniques described herein which comprise the present invention. Past attempts have been made as well to utilize twin screw extruders in the production of chewing gum, as indicated in U.S. Pat. No. 5,135,760, but such attempts have failed to recognize the effectiveness of properly equipped extruders in the reduction of gum density. Other patents disclosing modifications to twin screw extruders, such as U.S. Pat. No. 4,900,156 and U.S. Pat. No. 4,599,002, have not recognized or suggested the advantages available in the techniques of the present invention, and indeed have not described the production of chewing gums.